'The Big Bang Theory': Halloween episode preview

mw.setConfig('EmbedPlayer.EnableIpadHTMLControls', false ); mw.setConfig('Kaltura.ForceFlashOnDesktop', true ); Given a chance to scare anyone on "The Big Bang Theory," who would you pick? If you said anything other than Sheldon (Jim Parsons), you're probably telling a little bit of a fib. While you might not personally get the chance, Howard (Simon Helberg) and Raj (Kunal Nayyar) will do the dirty work for you in Thursday's (Oct. 27) Halloween episode. Of course Sheldon will do his part return the favor. In related "TBBT" news, Leonard's (Johnny Galecki) long-distance relationship with Priya faces challenges. The series airs at 8 p.m. ET....